2 files changed, 69 insertions, 18 deletions

diff --git a/video/mp_image_pool.c b/video/mp_image_pool.c
index 6b907706c5..c2d1fca080 100644
--- a/video/mp_image_pool.c
+++ b/video/mp_image_pool.c
@@ -43,6 +43,12 @@ struct mp_image_pool {
 
     struct mp_image **images;
     int num_images;
+
+    mp_image_allocator allocator;
+    void *allocator_ctx;
+
+    bool use_lru;
+    unsigned int lru_counter;
 };
 
 // Used to gracefully handle the case when the pool is freed while image
@@ -51,6 +57,7 @@ struct image_flags {
     // If both of these are false, the image must be freed.
     bool referenced;            // outside mp_image reference exists
     bool pool_alive;            // the mp_image_pool references this
+    unsigned int order;         // for LRU allocation (basically a timestamp)
 };
 
 static void image_pool_destructor(void *ptr)
@@ -102,43 +109,65 @@ static void unref_image(void *ptr)
         talloc_free(img);
 }
 
-// Return a new image of given format/size. The only difference to
-// mp_image_alloc() is that there is a transparent mechanism to recycle image
-// data allocations through this pool.
-// The image can be free'd with talloc_free().
-struct mp_image *mp_image_pool_get(struct mp_image_pool *pool, int fmt,
-                                   int w, int h)
+// Return a new image of given format/size. Unlike mp_image_pool_get(), this
+// returns NULL if there is no free image of this format/size.
+struct mp_image *mp_image_pool_get_no_alloc(struct mp_image_pool *pool, int fmt,
+                                            int w, int h)
 {
     struct mp_image *new = NULL;
-
     pool_lock();
     for (int n = 0; n < pool->num_images; n++) {
         struct mp_image *img = pool->images[n];
-        struct image_flags *it = img->priv;
-        assert(it->pool_alive);
-        if (!it->referenced) {
+        struct image_flags *img_it = img->priv;
+        assert(img_it->pool_alive);
+        if (!img_it->referenced) {
             if (img->imgfmt == fmt && img->w == w && img->h == h) {
-                new = img;
-                break;
+                if (pool->use_lru) {
+                    struct image_flags *new_it = new ? new->priv : NULL;
+                    if (!new_it || new_it->order > img_it->order)
+                        new = img;
+                } else {
+                    new = img;
+                    break;
+                }
             }
         }
     }
     pool_unlock();
+    if (!new)
+        return NULL;
+    struct image_flags *it = new->priv;
+    assert(!it->referenced && it->pool_alive);
+    it->referenced = true;
+    it->order = ++pool->lru_counter;
+    return mp_image_new_custom_ref(new, new, unref_image);
+}
 
+// Return a new image of given format/size. The only difference to
+// mp_image_alloc() is that there is a transparent mechanism to recycle image
+// data allocations through this pool.
+// The image can be free'd with talloc_free().
+struct mp_image *mp_image_pool_get(struct mp_image_pool *pool, int fmt,
+                                   int w, int h)
+{
+    struct mp_image *new = mp_image_pool_get_no_alloc(pool, fmt, w, h);
     if (!new) {
         if (pool->num_images >= pool->max_count)
             mp_image_pool_clear(pool);
-        new = mp_image_alloc(fmt, w, h);
+        if (pool->allocator) {
+            new = pool->allocator(pool->allocator_ctx, fmt, w, h);
+        } else {
+            new = mp_image_alloc(fmt, w, h);
+        }
+        if (!new)
+            return NULL;
         struct image_flags *it = talloc_ptrtype(new, it);
         *it = (struct image_flags) { .pool_alive = true };
         new->priv = it;
         MP_TARRAY_APPEND(pool, pool->images, pool->num_images, new);
+        new = mp_image_pool_get_no_alloc(pool, fmt, w, h);
     }
-
-    struct image_flags *it = new->priv;
-    assert(!it->referenced && it->pool_alive);
-    it->referenced = true;
-    return mp_image_new_custom_ref(new, new, unref_image);
+    return new;
 }
 
 // Like mp_image_new_copy(), but allocate the image out of the pool.
@@ -161,3 +190,16 @@ void mp_image_pool_make_writeable(struct mp_image_pool *pool,
     mp_image_steal_data(img, mp_image_pool_new_copy(pool, img));
     assert(mp_image_is_writeable(img));
 }
+
+void mp_image_pool_set_allocator(struct mp_image_pool *pool,
+                                 mp_image_allocator cb, void  *cb_data)
+{
+    pool->allocator = cb;
+    pool->allocator_ctx = cb_data;
+}
+
+// Put into LRU mode. (Likely better for hwaccel surfaces, but worse for memory.)
+void mp_image_pool_set_lru(struct mp_image_pool *pool)
+{
+    pool->use_lru = true;
+}
diff --git a/video/mp_image_pool.h b/video/mp_image_pool.h
index 6ea041c527..d9ab2ee9e1 100644
--- a/video/mp_image_pool.h
+++ b/video/mp_image_pool.h
@@ -8,6 +8,15 @@ struct mp_image *mp_image_pool_get(struct mp_image_pool *pool, int fmt,
                                    int w, int h);
 void mp_image_pool_clear(struct mp_image_pool *pool);
 
+void mp_image_pool_set_lru(struct mp_image_pool *pool);
+
+struct mp_image *mp_image_pool_get_no_alloc(struct mp_image_pool *pool, int fmt,
+                                            int w, int h);
+
+typedef struct mp_image *(*mp_image_allocator)(void *data, int fmt, int w, int h);
+void mp_image_pool_set_allocator(struct mp_image_pool *pool,
+                                 mp_image_allocator cb, void  *cb_data);
+
 struct mp_image *mp_image_pool_new_copy(struct mp_image_pool *pool,
                                         struct mp_image *img);
 void mp_image_pool_make_writeable(struct mp_image_pool *pool,